Rotary fluid motor



Sept l1, 1956 E. G. ROGGENBURK 2,762,340

ROTARY FLUID MOTOR 2 Sheets-Sheet l Filed Sept. 17, 1952 HHMOd-ISHOH 1N VEN TOR.

Sept. 1l, 1956 E. G. ROGGENBURK ROTARY FLUID MOTOR 2 Sheets-Sheet 2 Filed Sept. 17, 1952 INVENTOR.

fa/:N- @4f United States Patent O ROTARY FLUID MOTOR Earl G. Roggenburk, Cleveland, Ohio Application September 17, 1952, Serial No. 309,980

z Claims. (ci. 121-34) Y This invention relates to a new and improved rotary uid pump or motor of the sliding vane type, and more particularly to an improved end seal for the housing within which the vanes rotate.

An object of my invention is to provide an improved rotary pump or motor wherein the improvement arises from a better sealing of the housing and from a better method of assembling the pump.

It is an object of my invention to eliminate all scoring of the end plate by the vanes and rotor of a rotary pump or motor, thereby to improve the life and -eciency of the rotary pump or motor.

A further object of my invention is to provide a sliding vane rotary pump or motor wherein close manufacturing tolerances do not have to be maintained on a large number of the pieces used to make the pump or motor, thereby to produce a less expensive tool.

It is another object of my invention to provide a sliding vane rotary pump or motor which is more eicient when new and whose eiciency over the life of the tool is maintained at a higher level than existing pumps or motors.

Another object of my invention is to make a compressed air`driven rotary pump or motor which uses less air, and to protect the bearings, thereby to greatly extend the life of the bearings.

At the present time many plants have fixed or semixed facilities for producing compressed air. Only alimited number of pneumatic tools can be conected to the compressed air line. By providing a pneumatic tool which uses about 25 percent less air from the time it is manufactured until it is worn out, the user can connect 25 percent more tools to his compressed air supply.

For a better understanding of the present invention together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawing and its .scope will be pointed out in the appended claims.

Fig. 1 of the drawing is a graph showing the air consumption and the amount of air used per horsepower of the pump of the present invention compared to a prior art pump;

Fig. 2 is a sectional View showing the rotary pump; and

Fig. 3 is a sectional View taken along line 3 3 of Fig. 2.

With reference to the drawings, there is shown in Fig. l a graph having curves comparing the performance of the motor device of the present invention with the performance of a prior art device. There are three sets of data, each set of data being represented by two lines, and in each instance the dotted line shows the performance of the prior art device while the solid line shows the performance of the device of this invention.

The rst pair of curves compares the horsepower output of the two motors and shows that the horsepower of the prior art motor drops off very rapidly when the motor is rotating above about 3333 R. P. M., whereas the horsepower of the present motor does not start to drop off rapidly until the rate of rotation of the motor reaches lCe about 4450 R. P. M. This shows that there is a wide range of high speed tool operation where the prior art device is practically worthless.

The second pair of curves shows the air consumption for the prior art and the new device. The prior art device uses considerably more air from zero R.V P. M. upgthrough 3700 R. P. M. Above about 3700 R. P. M. the newmotor uses more air because it is capable of working hard in the upper speed range whereas the power output of the prior art motor has fallen to a point where it is incapable of doing effective work. In other words, at the speed where the old motor begins to use less air than the new motor,

the horsepower output of the old motor is so low thatv it is not capable of eifective use, whereas at that speed the new motor is .in its most powerful range. v -The third set of curves shows the air consumption per horsepower for the old and the new motors. This .is a.

horsepower, and at 3650 it uses about percent more v air per horsepower.

The primary reasons for -this outstanding decrease in the air consumption per horsepower and in the reduction in the total air consumed is the means for sealing the rotor in the rotor housing, and the method of assembling the motor to assure a very small running clearance between the two end plates and the two ends of the rotor.

The details of the construction of the motor, or pump,`

are shown in Figs. 2 and 3. y

The rotary motor is comprised of a housing 10 which preferably is generally cylindrical on the outside and com-k prises a forward section 11 and a rearward section 12 bolted together by four bolts 13 (only two of which are shown), extending through abutting anges 14, 1 5 in the two housing section 11, 12. The housing 10 is open in its interior defining a large cylindrical inner chamber.

A cylindrical liner 16 is positioned within the chamber in the housing 10 and the liner has a bore 17 which is Yeccentrically positioned with respect to the cylindrical opening in the housing 10. n

A shaft 20 extends into the inner chamber of the housing 10 and is eccentrically positioned with respect to the axis of the bore through the cylinder liner 16. y

A rotor body 22 is .integral with, or otherwise secured to, the shaft 20 and it has a plurality of slots 23 which extend in a direction parallel to the axis of the shaft 20 and radially with respect to the rotor. A sliding vane 24 is slidably positioned in each of the rotor slots 23 and as the rotor rotates, the outer end of each of the vanes 24 bears against ythe inner wall of the cylindrical housing liner 16 to eifect a seal to substantially prevent the passage of fluid, such as air, between each vane and the inner surface of the cylindrical lines.

`In order t-o support the mot-or 22 and the shaft 20 with respect to -the housing 110, there are provided two sets of bearing means, one at 'e'ach end of the rotor. Each `set of bearing means preferably 'comprises two lball bear- Iing assemblies 30, 31, the inner races of which are pressed onto the shaft 20 and the outer races 33 :of which are pressed under the 'outwardly extending porti-on 35 -of the end cap B6. Each end cap 36 is circular and Iits outer peripheral face 37 is in engagement with the inner `face of the housing :10. A shoulder 31S on the front por- -t-ion 1'1 of the housing 10 tirmly holds the front end cap 36 .in position, and the shoulder 39 'on the rearward housing portion 12 similar-ly holds the back end cap 36 in position. The innermost edge 40 `of each 'of Ithe end caps Y36 abut 4against the end faces 'of the cylindrical liner 16 to center the liner and hold it in position within the housing 110. t

' 'lwoV end* plates 45 are provided, one at each endrof the rotor for sealing thev two ends ofthe cylinder lin-er 16. Each end plate 45 .is forced ontothe' shaft portion 20 :of the rotor so that a positive *seallwis made between each end plate '45 .and the shaft 20. prevents 'any of the air which is driving the rotor' from escaping be'- tweenV the end plates 45 and the shaft 20v Vand protects both of the end Ybearings V3i), 3'1 from' moisture4 and sludge-carried by the air which drives'the rotor. Each of the end plates y45 has a close running tit with an end wall of the cylindrical liner '176 to form substantially an' air-tight seal to prevent the escape of the driving air' and the sludge n carries with if me the inenten of the end bearings, thereby to greatly prolong the life of the end bearings, and consequently, since it is usual-ly` the end bearingsk which lwear out iii-rst, to greatly prolong the life of theV entire motor. v shaft 20 arid with the Irotor 22 Iand rotor blades 24. Thus there -is no relative rotary mot-ion between the rotor blades and the end plates. This greatly improves the length and' quality of the air seal between the rotor blades and the en`d of the cylinder.

In the prior art the rotor blades rotated with respect to the ends of the cylinder andV as they were in frictional engagement with the cylinder ends to effect the required sealing engagement there was scoring of the cylinder ends and wear on the edges of the vanes. Also the rotor body would dig into the stationary end plates sometimes causing seizure between the parts. This rather quickly led to air' rleakage and reduced motor power. In the motor of this invention the end plates 45 form an effective air seal with the cylindrical liner along the sealing surfaces 50, 51, the sealing surface 50 being larger than the sealing surface 51 due to the eccentricity of the cylindricalv liner with'Y respect to the shaft 20 and the end plates 45. The fact that the sealing surface 50' is large is very valuable as it is near the air inlet port 52` where the air pressure is greater than it is at the outlet port 53, near the smaller sealing surface 51'. j v

It is desirable to 'have the peripheral end surface 55 of each end plate 45 in close running relationship to the inner surface of the portion 37 of the end caps 36 to improve the air seal, though this is not critical and if the end plate is made slightly undersize during manufacturing it need not be scrapped. This is one of the savings in manufacturing cost which is brought about by the use of cudV plates 45 whosel side faces seal with the end faces of the cylindrical liner 16.

The construction described is particularly useful in air motors, though other fluids may be used to drive the rotor. One of the problems faced by users of pneumatic motors is the moisture always present in the compressed air. This moisture is introduced into thepneumatic tool andl carries with it dirt, etc., which forms a wet sludge which interferes with the free running of the tool and causes rusting of bearings, gearsi etc. n

The construction shown in Figs. 2 and 3 gives the greatest protection to the bearings and causes almost all of the moisture and sludge to goout of the regular exhaust port 53 without contacting the bearings. There is of course a slight leakage of air around the end platesv 45. So long as there is a running fit with a' differential air pressure'on either side of the running tit' there is bound to be some leakage. In order that this'le'akage will cause the minimum of trouble the motor is provided withV two escape ports 60, one adjacent the peripheral edge of each of the' endplates 45 and located on the side of the plates 45 away from the rotor 22. Any moisture or sludge which gets past the air seal between the innerV face of the end plate 45 and the end face'of the cylindrical liner 16tends to fall to the lower portion of theumotorwhere `Vthe escape ports 60 are located. Centrifugal force act- The end plates 45 rotate with the ing on the moisture and sludge also tends to throw the' moisture and sludge toward the escape ports 60 where it passes out of the tool. This helps to protect the bearings which are positioned inwardly on the shaft 20.

The air which drives the rotor 22 enters the motor at the rear end 61 and travels under pressure through chamber 62, through valve opening 763 and passageway 64 to the inlet port 52 into the rotor chamber where it expands and drives the rotor with its interconnected drive shaft 20 and the exhaust air then flows out through the exhaust port 53. If the motor tends to run too fast the centrifugal force throws the weights 65 outwardly with a pivoting action causing the plunger 66 to move the valve 67 to shut the valve opening 63 and reduce the air supply to the motor.

An important feature of the invention is the method of assembling the motor to obtain the close running fits which permit the rotor to run freelyuyet keep the air leakage to a minimum. The rotor 22 is made about .002 inch longer than the cylindrical linerl. Two identical end assemblies are connected t'o the rotor shaft 20. Each end assembly comprises Atwo ball bearingl devices 30, 31 which fit around the shaft 20 with a shim 70 about .0041 inch thick located between the inner ball bearing 30 and the end plate 45. The governor mechanism serves as a bearing lock nut at one end and a lock nut is provided at the other end to Iholdl the bearings in place. An adjusting cap 71 is threaded over the outwardly extending portion 35 andvis in engagement with the ball bearing 31. Each adjusting cap 71 is turned until the inner face 45 of each end plate 45 is Hush with the outer edge 36' of the end cap 36. The sub-assembly comprising the rotor 22, rotor shaft 20', cylindrical liner 16 and the two end assemblies is then inserted into the housing section 11. When the housing section 1 2 is then bolted to the housing section 11 by means of the bolts 13, running clearance of about .001 inch is automatically provided along edges 40 between the end plates 45 and the ends of the cylindrical housing. If any adjustment is necessary it is a relatively simple matter to unbolt Vthe two housing sections 11 and 12, removeV the sub-assembly and either tighten or loosen either of the two adjusting caps 71, and to then replace the sub-assembly. The running clearance is obtained by slight shifting of each of the bearing means so that a distance of about on'ehalf of the difference in length between the 'rotor and the cylinder liner is provided betweenthe cylinder liner and the sealing face of the rotating end plates.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is: u

l. In a rotary motorga cylindrical housing; a cylindrical liner shorter in length than said cylindrical housing and having end sealing surface means positioned within said housing, said liner having a bore eccentrically positioned with respect to said housing; a rotor having radially extending slots mounted within said housing and having a shaft portion of diameter smaller than said rotor; vanes slidably mounted within said slots for sealing engagement with the inner wall of said cylindrical liner as said rotor rotates with respect to said housing;A bearing means mounted between said housing and s aidV shaft portion for rotatably supporting said rotor with respect to said housing; a circular end plate mounted around and in close frictional relationship to said' shaft portionr of said rotor at a location between said bearing means and said vanes for rotating with said rotor and having one of its faces inY close ninning overlapping relationship to the said end sealing surface means of said cylinder liner for sealing the end of said housing; and an end cap mounted between said housing and said bearing means, said end cap having a tubular threaded portion around said bearing means; and a threaded adjusting nut on the threaded portion of said end cap and in engagement with said bearing means for adjusting the axial loading on said bearing means and thereby to adjust the axial force between said bearing means and said end plate.

References Cited in the le of this patent 2. A rotary motor as set forth in claim 1, further 10 2'407613 characterized by two such end caps and threaded adjusting nuts, one at each end of said rotor.

UNITED STATES PATENTS Larimore Dec. 13, 1910 Kinsey Sept. 10, 1929 Vickers Feb. 21, 1933 Amtsberg Apr. 20, 1937 Fosnot Feb. 25, 1941 Schaedler Aug. 10, 1943 Mann et al. Sept. 10, 1946 

